Pipe rapper transmission mechanism



Feb. 15, 1&55

Filed June 12, 1953 w. J. BROWN ET AL 2,702,090

PIPE RAPPER TRANSMISSION MECHANISM 4 Shets-Sheet l INVENTORS AM J. BROWN WA [512- M. JOULE BY M 442 4 ATTORNEY Feb. 15, 1955 w. J. BROWN EI'AL P IPE RAPPER TRANSMISSION MECHANISM 4 Sheets-Sheet 2 Filed June 12, 1953 INVENTORQ WILLIAM J. BROWN WALTER M. JOUl E 1/ BY M M ATTORNEY Feb. 15, 1955 w. J. BROWN ETAL PIPE RAPPER TRANSMISSION MECHANISM Filed June 12, 1953 4 Sheets-Sheet 3 U q- E -1NVENTOR WILLIAM J,. BROWN WALTER M. JOULE BY A/MTM ATTORNEY Feb. 15, 1955 w. J. BROWN ET AL 2,702,090

PIPE RAPPER TRANSMISSION MECHANISM Filed June 12, 1955 4 Sheets-Sheet 4 l N VENTORS ATTORNEY WILLIAM J. BROWN WALTER M. JOULE PIPE RAPPER TRANSMISSION MECHANISM William I. Brown, Rm Brook, and Walter M. Joule, West Orange, N. 1., assignors to Research Corporation, New York, N. Y., a corporation of New York Application June 12, 1953, Serial No. 361,238

11 Claims. (CI. 183-7) This invention relates to an improved pipe rappirig mechanism for electrical precipitators, and has for its primary object the provision of an improved mecham sm for rapping the collector pipes of an electr cal precipitator in order to loosen and dislodge precipitated materials clinging to the inner walls of the collector electrodes.

A well'known type of electrical precipitator employs a plurality of vertically extending collector tubes through which a stream of dirty gas to be cleaned by electrical precipitation is passed. There is usually a central discharge electrode in each tube, a sufiiciently high potential being maintained between the central discharge electrode and the surrounding collector electrode so that small particulate material suspended in the gas is electiically charged and caused to move toward the collector electrode, settling on the inner walls thereof. It is customary to dislodge the collected material from these walls by periodically or continuously transnuttmg mechanical shocks to the collector electrodes, whereby the accumulated material is dislodged from the walls and falls to the bottom of the tubes by gravity. It has been found that in order to eflectively remove the precipitated material from the electrodes the mechanical shocks or vibrations transmitted to the tubes must be of considerable amplitude; however, they must not be of such force as to damage the structure. According to the invention, a mechanism is provided for directly rappingthe collector walls at a plurality of locations from a single driving source. The problem of striking a large number of different surfaces simultaneously involves the provisiofi of' means which will compensate for the inevitable misa gnments and mechanical tolerances due to differences in spacing between various members and surfaces involved. It is an important object "of the invention to provide such means, whereby a substantial number of collector electrodes may be rapped effectively from a single driving source, so that each electrode will obtain substantially equal rapping regardless ofthe inevitable misalignment and slight differences in dimensions of the various members.

Since the duty to which the rapping mechamsm is 2,702,090 Patented Feb. 15, 1955 'Fig. 1 is a plan view of an electrical precipitator provided with rappingv means according to the invention;

Fig. 2 is an enlarged plan view of a portion of the device shown in Fig. '1, showing details of the rapping mechanism;

3 is an elevational view taken on line 3-3 of ig.

Fig. 4 is a sectional view taken on line 4-4 of Fig. 2; Fig. 5 is a fragmentary elevational view taken on line 5-5 of Fig. 6; I

Fig. 6 is a similar view taken on line 6-6 of Fig. 5; 'Fig. 7 is a view partly in section taken along line 7-7 of Fig. 8 showing the eccentric drive and bearing plate subjected is necessarily very severe, it is a further object a to provide a simple and rugged mechanism capable of operating over long periods of time with little maintenance, and at the same time capable of ready replacement of worn or defective members when maintenance is required.

These and other objects and advantages are provided by the rapping means for at least two spaced electrodes of an electrical precipitator comprising a rod mounted for reciprocating movement transversely of the spaced electrodes carrying an electrode engaging member, spaced retaining members on said rod, opposed guide plates slidably mounted on said rod between said retaining members, means urging said guide plates in spaced relation against said retaining members, a second reciprocating rod slidably engaging said guide plates, second guide plate retaining members secured to said second reciprocating rod and normally engaging the outer faces of the opposed guide plates, and drive means for reciprocating said second rod.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings, in which:

mechanism; and V -8 is a sectional view taken along line 88 of Referring to Fig. 1, a precipitator generally indicated as 2 comprises a large number of vertically disposed collector ducts or tubes 4, each serving as the grounded electrode of a conventional electrical discharge system, not shown in the drawings, and each having a centrally disposed axially extending discharge electrode 6 in the form of a relatively fine wire or rod, the precipitating discharge taking place between electrodes 4 and 6 in the well known manner. The gas to be treated passes through collector tubes 4, and emerges therefrom into chamber 8 (Fig. 4). The precipitated material is attracted to the inner walls of the discharge tubes.4 and falls by gravity into a dust collecting chamber disposed at the bottom end of the collector tubes 4. In order to facilitate this action, and also to dislodge any material which may cling to the walls, means are provided for periodically rapping the outer walls of the collector tubes, the resulting vibration serving eflfectively to dislodge the accumulated material. The rapping is accomplished by cross-bars 10 pivoted on rapper shafts 12 which are caused to reciprocate axially so that each cross-bar 10 will first strike collector tubes 4a and 4b (Fig. 2) and then on its opposite reciprocal motion will strike collector tubes 40 and 4d, repeating this operation as long as the rapper shafts 12 are reciprocated. Each crossbar 10 is mounted, by means of pivot pins 10a, for limited pivotal motion on its associated rapper shaft 12 as best 0 shown in Fig. 6, which provides compensaition for slight inaccuracies in the relative pipe positions at the instant that the rapping occurs, and insures that each pipe of any pair such as 4a and 4b, or 40 and 4d, respectively, is struck with substantially equal force.

The reciprocating force is derived from externally located motors. Two such motors are shown at 14 and 14a in Fig. 1, each driving a separate group of rappers; however, since the two groups are perfectly symmetrical and identical in structure and function only one will be described in detail. Motor 14 drives shaft 16 through a conventional belt drive generally indicated at 18 in Figs. 2 and 4. Shaft 16 carries a number of eccentric members 20 which through cranks 22 deliver a reciprocating motion to tie bracket pins 24 and thence to tie brackets 28 and push rods 30 which are fixed to the tie bracket by means of nuts 32 for reciprocation therewith. Push rods 30 are carried in alignment through bearing plates 34 and 36 by bearings 40 and 42, respectively. Each push rod carries fixed to it collars 44 and 46 which bear on guide plates 48 and 50, respectively. Each pair of guide plates 48 and 50 carries a number of spring rods 52, three spring rods being shown in the modification illustrated. Each spring rod is coupled to the guide plates 48 and 50 by means of lock nuts 54 and retainers 56 which are slidably mounted on the spring rods and nuts 60 and 62 which are threadably secured thereon. A spring is provided on each spring rod, the springs being under strong compression to maintain the guide plates 48 and 50 in spaced relationship against nuts 60 and 62. The springs 58 are sufficiently rigid so that as the guide plates are reciprocated by means of push rods 30 through their collars 44 and 46, a necessary thrust is transferred through lock nuts 54 and thence through nuts 60 and 62 to the spring rods. However, if the force on the re- .spective springs 58 is sufliciently great, the guide plates the spring rods thus permitting compression of the springs 58 in either direction.

Spring rods 52 are coupled to one end of rapper shafts 12 through pins 64 so that the reciprocal movement continues along the axes of the respective rapper shafts 12, moving the latter in each direction for a portion of the stroke sulncient to cause cross arms 10 to rap successively one pair of pipes 4a and 4b and then on the opposite stroke to rap the other pair of pipes 40 and 4d, the pivotal connection between the rapper shaft 12 and rapper arms 10 insurin that both pipes of each pair are rapped with substantially equal force. The other ends of, rapper shafts 12 are supported for reciprocal movement in end guide plates 12a secured as by welding to the last row of collecting pipes of each group. The guide plates 12a are more clearly shown in Figs. 5 and 6 of the drawings. When the collecting pipes are contacted by the rapper arms either simultaneously or at different successive instance, spring rods 52 cease motion and a clearance is created at plane X (see Fig. 7) between nut 60 and retainers 56 and also between collars 46 and plate 50, because overstroke of the eccentric is now taken by deflection of rapper springs 58. This action allows for a possible relative difference in stroke required between neutral position and actual rapping contact at the respective pipes.

Reverse action is now obtained by continuing rotation of the eccentric causing motion in the opposite direction. The initial result of reversal is that clearance at X" is taken up by extension of springs 58 in consonance with reversal of thrust from collars 44 to collars 46. The power side of the mechanism thus transfers from one set of guide plates to the other, which continues in the manner previously described in the opposite direction, until the rapper arms strike the opposite pair of collecting pipes and overstroke occurs creating a clearance on theopposite set of guide plates at plane X similar to that previously described. It will thus be seen that exact tolerances are not needed and approximately equal rapping of all of the pipes of the system is assured. It will be understood that the springs 58 are sufficiently rigid to permit a substantial and effective rap to be transmitted to each set of collector pipes or tubes. The driving motor 14 must, of course, be sufficiently powerful to compress if necessary all of the springs of the system simultaneously. However, as the stored energy of the springs assists in .the beginning of the following stroke, there is very little loss of total energy in the system. It will be noted that the above described system does not require close tolerances in either the locations of the precipitator collector tubes or in the components of the rapper transmission mechanism which is constructed of a relatively few simple rugged interchangeable components and can be built up largely of standard inexpensive elements.

It will be apparent that the embodiments shown are only exemplary and that various modifications can. be made in construction and arrangement within the scope of our invention as defined in the appended claims.

We claim:

1. Rapping means for at least two spaced electrodes of an electrical precipitator comprising a rod mounted for reciprocating movement transversely of the spaced electrodes carrying an electrode engaging member, spaced retaining members on said rod, opposed guide plates slidably mounted on said rod between said retaining members, means urging said guide plates in spaced relation against said retaining members, and reciprocating drive means for said rod operatively engaging said guide plates in a direction opposed to said means urging said guide plates in spaced relation.

2. Rappin means for at least two spaced electrodes of an electrical precipitator comprising a rod mounted for reciprocating movement transversely of the spaced electrodes carrying an electrode engaging member, spaced retaining members on said rod, opposed guide plates slidably mounted on said rod between said retaining members, means urging said guide plates in spaced relation againstsaid retaining members, a second reciprocating rod slidably engaging said guide plates, second guide plate retaining members secured to said second reciprocating rod and normally engaging the outer faces of the opposed guide plates, and drive means for reciprocatrng said second rod.

3. In combination with at least two spaced elements of an electrical precipitator, rapping means for reciprocating back and forth between said elements and striking them alternately, reciprocable elongated rapper means axially movable and carrying said rapping means, two parallel spaced guide plates having aligned bearings through which said rapper means pass, said rapper means being axially slidable in said bearings, spring means bearing against the opposed inner faces of said guide plates, two collars fixed to said rapper means and bearing against the respective outer faces of said guide plates, two further bearings aligned respectively in said guide plates, a push rod passing through said last bearings andaxially movable therein, two push rod collars fixed to said push rod and bearing against the respective outer surfaces of said guide plates, and means for axially reciprocating said ,push rods, whereby thrust from said push rods is transmitted to said elongated rapper means through said spring means.

4. The invention according to claim 3, said guide plates carrying a plurality of similar elongated rapper means.

5. The invention according to claim 4, said guide plates carrying a plurality of similar push rods.

6. The invention according to claim 3, said rapping means comprising an elongated striker arm pivotally and transversely mounted on said rapper means for limited pivoted motion thereon, and having two arms respectively extending on opposite sides of said rapper element for striking two spaced elements of said precipitator simultaneously on each reciprocation of the rapper element.

7. The invention according to claim 6, said guide plate carrying a plurality of similar elongated rapper means.

8. The invention according to claim 7, and an eccentric driver for reciprocating said push rod.

9. The invention according to claim 8, including a shaft for said eccentric driver, motor means for rotating said shaft, a plurality of similar eccentric drivers on said shaft, and a lurality of similar rapping mechanisms respectively drrven by said eccentric drivers.

10. The invention according to claim 3, said spring means comprising a coil spring wrapped around said elongated rapping means between said guide plates.

11. The invention according to claim 10, said rapper means comprising a spring rod passing through said first bearings and a rapper rod pivotally fastened to said spring rod, said spring rod and rapper rod extending substantially in axial alignment.

References Cited in the file of this patent UNITED STATES PATENTS 1,339,471 Meston May 11, 1920 1,463,352 Weiskopf July 31, 1923 FOREIGN PATENTS 286,390 Great Britain Mar. 8, 1928 364,808 Germany Dec. 1, 1922 

